---
title: "AIS.TR.355 Terrain data sets — SPECIFIC REQUIREMENTS FOR THE PROVIDERS OF AERONAUTICAL INFORMATION SERVICES, ATM/ANS · Avioverse"
description: "When terrain data sets are provided in accordance with point AIS.OR.355:"
url: "https://avioverse.aero/regulations/easa/atm-ans/specific-requirements-for-the-providers-of/subpart-b/ais-tr-355"
---

# AIS.TR.355 Terrain data sets

SPECIFIC REQUIREMENTS FOR THE PROVIDERS OF AERONAUTICAL INFORMATION SERVICES · Regulation (EU) 2017/373 · EAR revision 12 Mar 2025

IR Implementing rule

## AIS.TR.355 Terrain data sets

When terrain data sets are provided in accordance with point AIS.OR.355:

(a) terrain data sets shall contain the digital representation of the terrain surface in the form of continuous elevation values at all intersections of a defined grid, referenced to a common datum;

(b) a terrain grid shall be angular or linear and shall be of a regular or irregular shape;

(c) terrain data sets shall include spatial (position and elevation), thematic, and temporal aspects of the surface of the Earth, containing naturally occurring features, excluding obstacles;

(d) only one feature type, i.e. terrain, shall be provided;

(e) the following terrain feature attributes shall be recorded in the terrain data set:

(1) area of coverage;

(2) identification of the data originator er;

(3) data source identifier;

(4) acquisition method;

(5) post spacing;

(6) horizontal reference system;

(7) horizontal resolution;

(8) horizontal accuracy;

(9) horizontal confidence level;

(10) horizontal position;

(11) elevation;

(12) elevation reference;

(13) vertical reference system;

(14) vertical resolution;

(15) vertical accuracy;

(16) vertical confidence level;

(17) recorded surface;

(18) integrity;

(19) date and time stamp; and

(20) unit of measurement used;

(f) Within the area covered by a 10-km radius from the ARP, terrain data shall comply with the Area 2 numerical requirements;

(g) in the area between 10 km and the TMA boundary or a 45-km radius, whichever is smaller, data on terrain that penetrates the horizontal plane 120 m above the lowest runway elevation shall comply with the Area-2 numerical requirements;

(h) in the area between 10 km and the TMA boundary or a 45-km radius, whichever is smaller, data on terrain that does not penetrate the horizontal plane 120 m above the lowest runway elevation shall comply with the Area-1 numerical requirements; and

(i) in those portions of Area 2 where flight operations are prohibited due to very high terrain or other local restrictions and/or regulations, terrain data shall comply with the Area-1 numerical requirements.

Terrain data collection surfaces – Area 1 and Area 2

\[Figure or form omitted from this preview — available in the Avioverse workspace library.]

IR · AIS.TR.355 — Regulation (EU) 2017/373 · Commission Implementing Regulation (EU) 2020/469 · ATM/ANS Easy Access Rules · EAR revision 12 Mar 2025

GM Guidance material

## GM1 AIS.TR.355(e) Terrain data sets

ATTRIBUTES

The following additional terrain feature attributes may be recorded in the terrain data set:

(a) surface type;

(b) penetration level; and

(c) known variations.

GM · GM1 AIS.TR.355(e) — Regulation (EU) 2017/373 · ED Decision 2020/008/R · ATM/ANS Easy Access Rules · EAR revision 12 Mar 2025

[All rules in SUBPART B — TECHNICAL REQUIREMENTS FOR PROVIDERS OF AERONAUTICAL INFORMATION SERVICES (AIS.TR)](https://avioverse.aero/regulations/easa/atm-ans/specific-requirements-for-the-providers-of/subpart-b)

Consolidated from the EASA Easy Access Rules (revision 12 Mar 2025, extracted 13 Oct 2026) for convenience. Not the official publication — verify against the Official Journal of the European Union and the EASA publications before operational use.